1 files changed, 34 insertions, 9 deletions

diff --git a/io_uring/alloc_cache.h b/io_uring/alloc_cache.h
index a3a8cfec32ce..cca96aff3277 100644
--- a/io_uring/alloc_cache.h
+++ b/io_uring/alloc_cache.h
@@ -6,6 +6,19 @@
  */
 #define IO_ALLOC_CACHE_MAX	128
 
+#if defined(CONFIG_KASAN)
+static inline void io_alloc_cache_kasan(struct iovec **iov, int *nr)
+{
+	kfree(*iov);
+	*iov = NULL;
+	*nr = 0;
+}
+#else
+static inline void io_alloc_cache_kasan(struct iovec **iov, int *nr)
+{
+}
+#endif
+
 static inline bool io_alloc_cache_put(struct io_alloc_cache *cache,
 				      void *entry)
 {
@@ -23,35 +36,47 @@ static inline void *io_alloc_cache_get(struct io_alloc_cache *cache)
 	if (cache->nr_cached) {
 		void *entry = cache->entries[--cache->nr_cached];
 
+		/*
+		 * If KASAN is enabled, always clear the initial bytes that
+		 * must be zeroed post alloc, in case any of them overlap
+		 * with KASAN storage.
+		 */
+#if defined(CONFIG_KASAN)
 		kasan_mempool_unpoison_object(entry, cache->elem_size);
+		if (cache->init_clear)
+			memset(entry, 0, cache->init_clear);
+#endif
 		return entry;
 	}
 
 	return NULL;
 }
 
-static inline void *io_cache_alloc(struct io_alloc_cache *cache, gfp_t gfp,
-				   void (*init_once)(void *obj))
+static inline void *io_cache_alloc(struct io_alloc_cache *cache, gfp_t gfp)
 {
-	if (unlikely(!cache->nr_cached)) {
-		void *obj = kmalloc(cache->elem_size, gfp);
+	void *obj;
 
-		if (obj && init_once)
-			init_once(obj);
+	obj = io_alloc_cache_get(cache);
+	if (obj)
 		return obj;
-	}
-	return io_alloc_cache_get(cache);
+
+	obj = kmalloc(cache->elem_size, gfp);
+	if (obj && cache->init_clear)
+		memset(obj, 0, cache->init_clear);
+	return obj;
 }
 
 /* returns false if the cache was initialized properly */
 static inline bool io_alloc_cache_init(struct io_alloc_cache *cache,
-				       unsigned max_nr, size_t size)
+				       unsigned max_nr, unsigned int size,
+				       unsigned int init_bytes)
 {
 	cache->entries = kvmalloc_array(max_nr, sizeof(void *), GFP_KERNEL);
 	if (cache->entries) {
 		cache->nr_cached = 0;
 		cache->max_cached = max_nr;
 		cache->elem_size = size;
+		cache->init_clear = init_bytes;
 		return false;
 	}
 	return true;